The present invention relates to cable adjustment devices and more particularly to a cable adjustment device for bicycle brake and shifting systems.
Manually actuated bicycle brakes and shifting systems are actuated by operating brake or shift levers that are located on the handlebars and connected to front and rear brakes and derailleurs by Bowden cables. Typically, the Bowden cable includes a control cable displaceable within an outer casing. To adjust the control cable, an adjustment device is located at one or both ends of the outer casing.
EP 0 727 349 A2 discloses an adjustment device for a Bowden cable including a control cable and an outer casing, with the control cable protruding from the casing at both ends. The adjustment device includes a guide element, an adjustment element that is screwed into a threaded bore, a coil spring, and an actuation element. The guide element receives the control cable and includes an abutment for engaging the outer casing, while permitting the control cable to extend therethrough. The guide element is supported in the adjustment element, which may be screwed into a corresponding thread bore of a bicycle component by a screw thread to adjust the length of the control cable. The adjustment element is rotationally connected to the actuation element by a driving contour. A coil spring is disposed between the actuation element and the adjustment element for pressing the actuation element, which includes a detent contour, against a corresponding contour on the bicycle component to rotationally fix it.
A benefit of this adjustment device is that the position of the actuation element remains unchanged when the adjustment element is adjusted. However, when the actuation element is twisted, the exit point of the control cable from the guide element is displaced relative to the bicycle component, which is undesirable for control cables used in shifting systems. Further, the actuation element and the coil spring may be lost during installation of the adjustment device because they are loosely attached to the adjustment element.